Telephone-exchange system



Dec. 2, 1924' F. J. SCUDDER TELEPHONE EXCHANGE SYSTEM Filed Sept. 22

92] 4 Sheets-Sheet l F. JJSCUDDER TELEPHONE EXCHANGE SYSTEM Dec. 2 1924 1,517,257 F. J. SCUDDER TELEPHONE EXCHANGE SYSTEM Filed Sept. 22. 192] 4 Sheets-Sheet 5 Dec. 29 1924- Dec. 2, 1924. 1,517,257 F. J. SCUDDER TELEPHONE EXCHANGE SYSTEM Filed Sept. 22, 1921 4 Sheets-Sheet 4 Patented Dec. 2, 1924.

UNITED STATES PATENT OFFICE.

FREDERICK J. sccnnnn. or UEE'Ns, Lone Is ANnnEw YORK, AssIGNoR. 'IO West:-

can ELECTRIC COMPANY, INCORPORATED, ornnw YORK. N. Y. A conroniimon OF NEW YORK.

TELErI IONE-EXCHANGE SYSTEM.

Application and September 22, 1921. Serial No. 502,503.

To all when. it /nicg concern:

Be it known that I, Fnnnnnicn J. SCUB- nnn, a citizen ot the United Statea'residing at Queens. Longlslaml, in the county of Queens State of New York, have invented certain new and useful Improvements in Telepl'ione-Exchange Systems, of which the following is a full, clear, concise. and exact description.

This invention relates to telephone eX- change systems, and more particularly to systems involving the use o t machine switchineapparatus tor the establishment of con-c nections.

In certain types of exchange systems where connections are extended to subscribers lines by lneans ot trunks and oper ators connecting circuits, it'is desirable under some circumstances r01- the operator, at

ter the call has progressed to a given point, i to temporarily withdraw or to change herconnecting circuits. For example, intoll switching practice the operator causes a connection to behuilt up over a trunk, lad- 7 ing from her position, and automatic switcl'ies to the subscribers line.

the other'party, the operator inserts ahold 'ing cord temporarily in the jack of the trunk iuvolvedj Attersecuring the desired party it is then necessary'tor her to remove the holding cord theretor one of her regular connecting circuits. thereby interconnecting the calling and called lines tor conversation I Since the release of the autol'natic switches results 'lron'i the usual acts ot the operator in takeng down the connection, some provision must be made to allow her to ten'iporarily remove her connecting cir 111' Order to hold the connection and prevent'lts se1zure in the meantime, while she 1s obtamingl I cuits. circuit and SHbSiZIiJUlJQ automatic provision of a time counting switch responsive to the disconnection of the op'eiw ators circuit from a trunk to cause the re. lease, after an interval of time, of the automatic switches to which said trunk leads and means whereby said time counting switch is rendered inetl'ective if the operator again makes connection with said trunk before said. interval expires.

Another feature of the invention is a counting. switch of the above mentioned character having a plurality of normal positions. associable when in one of its normal positions with a trunk and so arranged that, when the operator disconnects her connecting circuit from a trunk while said switch is in some position other than nor mah its association With such trunk is delayed until said switch reaches its next normal position.

These and other features contemplated in the present invention will. become more thoroughly understood from a consideration of the "following description.

Referring to the drawing Figs. 1 to 4 when taken in order from left to right disclose a portion OfL telephone exchange system embodying the subject matter of this invention.

Fig' 1. shows a. toll operators position including a pair of the operators cord cir- This figure also shows a called sub= scribersline which is reached over trunks by the toll operator and the. outgoing end of the trunk leading to an automatic switch accessible to the toll operator for extending connections to the calling sul'iscribers lines.

Fig. 2 illustrates in diagrammatic lorm one of a plurality of switehinn units serx ing a plurality of the trunks outgoing from the operators position-. a register sender and a portion of the toll operators keyboard. This figure in addition illustratesthe time counting switch arranged in common to all the trunks leading from the toll operators position, the "Function of which will be described later.

Fig". 3 shows an incoming selectorswitrh in which the trunk shown extending from the toll operators posltion terminates.

F 1g. 4 illustrates a final selector switch lit having access to calling subscribers lines and one of said lines.

While the invention in one aspect relates to the time counting or measuring device common to a plurality of trunks or connecting circuits and associable with any one of said trunks in response to some act performed upon such trunk to cause at the end of an interval of time, the release of automatic switches at the distant end of said trunk provided some subsequent act is not performed upon the trunk in the meantime to render the time measuring device inef- .fective, has been illustrated in this application in connection with the trunks at a toll. operatoi"s position. In the particular embodiment hero disclosed, the toll operators position equipped with register send-1 ers, a sender controlling keyboard and a plurality of automatic switching units for selecting an idle trunl: leading-in the proper direction. for associating an idle register sender with the selected trunk and for associating the operators keyboard with said register sender.

Tn Fi g. 2 there is shown schematically one of the registersenders 20 1-, aportion otthe operator-s sender controlling keyboard 203 and one of the switching units including switches 200, 201 and 202. These switches all operate simultaneously, their movement being initiated by the toll operator, the switch 200 serving to find an idle trunk 118, 119 in the group leading in the direction of the callin subsoribers line, the

switch 201 operating to select an idle register sender 204 and the position selector switch 202 acting to find the toll operators position handling the call. The register sender 204C, having been selected and associated with the operators keyboard, may beset in accordance with the designation of the calling subscribers line which has been given the toll operator and thereafter serves as will be explained later to control the incoming and final switches shown in .l igs. Band 41; to extend the selected trunk 118, 119 from the toll operntofis position to the a calling sulascribefis line. The controlling and switching equipment located at the toll. operators position may be of the same type as the one shown in detail and described in an application by L. \(l. Allen Serial No. 502, 17 1, filed September. 22, 1921.

The, selector switches shown in Figs. 3 ands are of the well-known revertive impulse control power driven. type and may be in general the same as the one described in the patent to Craft and Reynolds No. 1,123,696, issued January 5, 19175.

In order to describe the functions of the time counting device which permits an operator to disconnect her talking circuits from an outgoing trunk for an interval of time material herein.

in the process of establishing a connection Without releasing the switches to which the trunk leads, an explanation will he made of the process involved in the establislnnent of a toll connection. Assume, that the toll operator whose position and equipment is shown in Figs. 1 and 2 has received the information regarding a desired toll call. This information includes the number of the calling subscribers line 130, shown in Fig. 1, the nameof the oiiice containing such line, the name of the oflice coi'itaining the called subscribers line 100 and the number of such line. The methodin which the information is given the toll operator is not It may come to her over an order wire from another operator, or in the form of a ticket from a recording operator. Having learned the name of the otlice. and the number of the calling sub scribers line therein, the toll operator depresses a key, not shown, individual to such office and initiates the movement of one of the switching units, diagrammatically illustrated by the switches 200, 201 and 202, in

dividual to the trunks leading to the sw1tches shown in Figs. 3 and 41 having access to the l1nes 1n the office containing the calling line 130. The toll operator inaddition, sets up the number of the calling subscribers line 011 her keyboard 203 which causes the setting of the registers of the sender 2041. 7

After the trunk selector switch 200 of the switching unit has selected an idle trunk 118, 119 in the proper group and the position selector switch 202 has chosen the operators position, a visual indication of the identity of the selected trunk is displayed before the operator in order that she may know which one of the total number of trunks she is to employ in making the connection.- Observing the indication of the trunk selected, the operator seizes the plug 1.16 of a holding cord circuit 115 and inserts it in the jack 117 of such trunk. The holding cord 11:") is for the purpose of maintaining the set condition of the succeeding switches, which later establish the connection from the trunk 118, 119 to the calling subscribers line in order that said line cannot be seized by other switches and made busy during the time that the toll operator is obtaining the distant called subscribers line. 116 in the jack of the selected trunk completes a circuit from battery, over the sleeve of said. plug and jack, conductor 120, winding of relay 207 to ground. Relay 207 operates and at its outer right contact places a ground potential on the terminal. 220 and all multiples of said terminal in other trunk selector switches similar to switch 200. to render such trunk non-selectable.

The insertion of the plug.

After the register sender has taken its complete setting in accordance with the designation of the calling subscribers line, the fundamental circuit is completed for coi'itrolling the brush selecting operation of the incoming selector switch shown in Fig. 3. This circuit may be traced from battery through the right-hand windng of relay 305, lower left contact 309 (1+3), lower right contact 309 (1), lower left contact 313 (1+i), lower right contact 306 (1+9), conductor 335, conductor 221, brushes 222 and 223, contact of relay 206, winding of stepping relay 205, brushes 22 iand 22 i, conductors 220 and 336, lower and upper left contacts 307 (1+9), to ground. delays, 305 and 205 ener ize in the fundamental circuit and the former of these completes a circuit from ground through its outer front contact, lower left contact 312 (1), winding of sequence switch magnet 310 to battery. Sequence switch 310 moves out of position 1 into position 2, where a circuit is closed for the updrive power magnet 313. This circuit may be traced from battery through the winding of said magnet, upper right contact of spring 312 outer front contact of relay 305 to ground. in position 2 of the sequence switch, relay 305 is main tained energized in a circuit from battery through its right-hand winding and inner front contact, lower left contact of spring 315 (1+4), thence over the fundamental. circuit to ground as described.

The updrive power magnet 318 causes the brush shaft 337 to more upwardly and for each brush tripping position passed over, a circuit is closed as follows for sluinting out the stepping relay 205 in the fundamental circuit, maintaining the relay 305 operated: Battery,through the right-hand winding and inner front contactof relay 305, lower left contact of spring 315 (1+4), upper right contact of said spring (1 %{2), coinmutator 330, brush 323, left contact of spring 313 (7+5), to ground. The stepping relay 205 is deenergized each time the above traced shunt circuit is closed and the register sender operates to thiteriniue the amountof movement iinpzu'ted to the switch. When the proper set of brushes is reached, the sender opens the fundamental circuit and as soon thereafter as the brush 328 engages an insulating segment of commutator 330, the relay 305 retracts its arn'iatures'and opens the circuit of the updrive power magnet 318. Relay 305 also closes a circuit from ground through its outer back contact, left contact of spring 311 (2), winding of sequence switch magnet 310 to battery, driving said sequence switch out of position 2 and into position 3.

in position 3 of sequence switch 310, the fui'uhmiental circuit is again closed in the manner above described and relay 305 at its outer front contact closes the previously traced circuit for advancing i. equence switch. 310 into position 4. In position 4t. re lay 305 remains energized. and completes the circuit for the updrive power magnet 313 for the upward i'noven'ient of the brush shaft in the group selecting operation The tripping magnet 319 energizes in position 3 of sequence switch 310 over a circuit closed at the lower contacts of sequence switch spring 314 and positions the tripping spindle so that on the second upward movement of the brush shaft the selected set of brushes are tripped to encounter the multiple terminals of the bank. For each group of terminals traversed by the tripped set of brushes, a circuit is closed from battery through the right-hand. winding and inner front contact of relay 305, lower left contact of spring 315 (Ll-i), upper left contact of spring 305 (3 W -t4), commutator 331, brush 327, to ground. The closure of this circuit holds the relay 305 energized and shunts out the stepping relay 205 in the fundamental circuit. hen the register of the sender 204 has become satisfied, the fundan'ieutal circuit is opened. and relay 305 becomes do energized immediately that the brush 327 encounters the next insulating segment of commutator 331. lelay 305 opens the circuit of the power magnet 313 and completes a circuit from ground througl'i its outer back contact, left contact of spring 311, through the winding of tequence switch. 310 to battery, driving the sequence switch into position 5.

In position 5 of sequence switch 310, a circuit is closed from battery through the left-hand winding of relay 305, lower right contact of spring (5+6), lower left coni'iiCll said spring to ground. relay 30:) operates and locks in the following circuit, provided the first trunk in the group, upon the terminals of which the brushes 321, 322 and 323 are now staruling, is busy: Battery, through the right-hand winding and inner front contact of relay 30?, upper left contact of spring 314E (5+7' upper right contact of said spring (5-|lii), brush 323 to the grounded test tern'liual of the busy trunk. ltelay 305 at its outer front contact closes a circuit including the lower left contact of spring 312 for driving sequence switch 310 into position 6. Relay 305 remains energized in this position and completes a circuit through its outer front contact and the upper right contact of spring 312 (0) for the updrive power magnet 318, whereby the brush shaft 337 is driven upwardly to advance the brushes 321, and 323 over the terminals of the group to hunt for an idle trunk line. When the first idle trunk is reached, no ground potential being present upon the test terminal. the holding circuit of relay 305 is energized for an instant by means of a circuit from battery through the left-hand winding of said relay, lower rightcontact ot spring 334 (+6), upper right contact of said spring (6), commutator 332, brush 329, lower right contact of spring 312 (6), outer front contact of relay 305 to ground. When the brush 329 ei'igages the next insulating segment of commutator 332, relay 305 is deenergized and the circuit of the magnet 318 is opened, causing the brush.

shaft to cease its upward n'iovement. Relay 305 at its outer back contact closes a circuit for driving the sequences switch 310 out of position and into position 7.

In position 7 of sequence switch 310, a circuit is closed from battery through the right-hand winding of relay 305, lower left contact of spring 309 (7), upper right contact of said spring (7+16), lower contact of spring 310 (7+8), brush 322, trunk conductor 325, upper left contact of sequence switch spring 411 (17 +15), lower right contact of said spring (1+8 to ground. clay 305 becomes energized and closes a circuit through its outer front contact for driving sequence switch 310 out of position 7; into position )Vhile sequence switch 310 is moving from position 7 to position 7 relay 305 is held energized in a circuit from battery through the right-hand winding and inner front contact of said relay, upper left contact of spring 314 (5+7 lower left contact of said spring (6 to ground. When sequence switch 310 reaches position 7 the following circuit is closed for relay 305 in which said relay is maintained energized after the sequence swltch 1 has moved into position 8: from battery,

through the right-haml winding and inner front contact of relay 305, lower right contact pring 309 (7 ]-8) upper right contact of said spril'ig and thence to ground at sequence switch spring 4.1.1.

The trunk324, 325 selected by the incoming switch is held busy so as not to be sellectaliilc by other switches by means of ground potential placed on the test conductor 326. Fhis potential is applied from' ground through the lower left contact of spring 31 1 (6%+1G%), upper right contact of said spring (5+15), test brush 323 and thence to the multiple terminals of the test conductor 326 before all other switches.

The fundamental circuit for controlling the brush tripping movement of the final selector switch. shown. in Fig. at is now completed and may be traced from battery through the winding ofrelay 100, lower left contact of spring 108 (1), lower contacts of spring 412 (-1-6), conductor 32%, brush 321, lower right contact of spring 315 (8), lower right contact of spring 306 (1+9), conductor 335, thence through the stepping relay 205 at the sender and returning hereinbefore traced, over conductor 330 to ground at spring 307. Relay 4:00

and the stepping relay 205 operate in this circuit. Itelay 400 closes acircuit from ground thr ugh its left front contact, lower right contact of spring 4103 (1), winding of sequence switch magnet 4110 to battery, driving said sequence switch into position 2."

Relay remains energized in position 2 of the sequence switch by means of the circuit from battery through its winding and the right contact, lower right contact of spring 4108 (1+6), lower contacts of spring 4112 (15+6), comli'ictcr 32 1- and thence over the tundamental circuit as traced to ground.

llelay 4100 by remaining energized in position 2 of the sequence switch establishes a circuit from battery through the winding of the updrive power magnet 113, spring 400, closed in position 2, left front contact of relay 400 to ground. Magnet 4e13causes the brush shaft 128 to be driven upwardly in the brush selecting ,nrovbment. Each time a brush tripping position is passed, a circuit is closed as follows for shunting the stepping relay 205. in the fundamental circuit: Battery, through the winding and right contact of relay 4:00, lower right con tact of spring 4:08 (1+6), lowerright contact of spring 112 (15+6), upper right con.- tact of said spring (1 +2), commutator 42 1, brush 422 to ground. At the end of the brush tripping movement, the fundamental circuit is opened at the sender and when thereafter the brush 422 moves on to an insulating segment of commutator 4121,.

relay 100 dee-nergizes, opens thecircuit of the magnet 413 and closes a circuit through its left back contact and the upper right contact of sprin 1503 for dririn se uence' relay 100 attracts its arinatures and a circult is closed. over the lower right contact of spring 4t03 for driving sequence t-iiriitill 410 into position 4.. Relay 400 renntiuii'ig energized in' position 1 completes the circuit hereinbefore traced including spring 4106 for energizing the updrive power magnet 113. With the tripping magnet i1 1. energized in positions 3 and 4: of the sequence switch in a circuit including spring 407, the subsequent upwardUmovement of the brush shaft 128 in the group selecting operation trips the chosen set of brushes 116, 417 and 4-18, whereby the same are driven over the terminals of the bank. For each group of the trunks traversed by the brushes, a circuit is completed as follows for shunting the stepping magnet 205 Battery. through the winding and right contact of relay 4:00, lower rigl'it contact of spring ill) litter the register sender has taken its complete setting in accordance with the designation-of the calling subscribers line, the Fundamental circuit is completed for controlling the brush selecting operation of the incoming selector switch shown in F 3. This circuit may be traced from battery through the right hand 'windng of relay 305, lower left contact 309 (1+3), lower right contact 309 (1), lower left contact 315 (1+4), lower right contact 306 (1+9), conductor 335, conductor 221, brushes 222 and 223, contact of relay 200, winding of stepping relay 205. brushes and Q23. conductors 22-0 and 330, lower and upper left contacts 307 (1+9), to groi'ind. Relays 305 and 205 energize in the fumlamental circuit and the former of these completes a circuit from ground through its outer front contact, lower left contact 312 winding of sequence switch magnet 310 to battery. Sequence switch 310 moves out of position 1 into position 2, where circuit is closed for the updrive power magnet 3 8. This circuit may be traced from. battery through the winding of said magnet, upper right contact of spring 312 (2), enter front contact of relay 305 to ground. in position 2 of the sequence switch, relay 305 is maintained energized in a circuit from battery through its right-hand winding and inner front contact, lower left contact of spring 315 (1+4), thence over the fundamental circuit to ground as described.

The updrive power magnet 318 causes the brush shaft 337 to move upwardly and for each brush tripping position passed over, a circuit is closed as follows for shlmting out the stepping relay 205 in the fundamental circuit, maintaining the relay 305' operated: vBattery, through the right-hand winding and inner front contact of relay 305-, lower left contact of spring 315 (1+4), upper right contact of said spring (1 .1-1-2), commutator 330, brush 328, left contact of spring 3 3 (7+5), to ground. The stepping relay 205 is deenergized each time the above traced shunt circuit is closed and the register sender operates to determine the amount of movement imparted to the switch. W hen the proper set of brushes reached, the sender opens the fundamental circuit and as soon thereafter as the brush 328 engages an insulating segn'ient of commutator 330, the relay 305 retracts its armat-ures and opens the circuit of the updrive power magnet 3 .8. clay 305 also closes a circuit from ground through its outer back, contact, left contact of s in'ing 311 winding of sequence switch magnet 310 to battery, driving said sequence switch out of position 2 and into position 3.

In position of sequence switch 310, the .fruulamental circuit is again closed in the trimmer above described and relay 3053 at its outerfront contact closes the pre yio'usly traced circuit for ad 'ancin'g sequence switch 310 into position i. inposition 4. rclay305 remains energized and crunplctcs the circuit for the rqulrive power magnet 318 for the upward movement of the brush shaft 337 in the group selecting operation. tripping magnet 319 energizes in position 3 of sequence switch 310 over a circuit closed at the lower contacts of sequence switch spring 314 and positions the tripping spindle so that on the second upward movement of the brush shaft the selected set of brushes are tripped to encounter the n'niltiple tm'minals of the bank. For each group of tern'rinals traversed by the tri, ped set of brushes, a circuit is closed from battery through the right-lutnd winding and inner front contact of relay 305, lower left contact of spring 315 (1+4), upper left contact of spring 306 i+4:), commutator 331, brush 327, to ground. The closure of this circuit holds the relay energized and shunts out the stepping relay 205 in the fundamental circuit. hen the register of the sender 204 has become satisfied, the fundamental circuit is opened and relay 305 becomes deenergized immediately that the brush 3L7 encoimters the next insulating segment of commutator 331. Relay 305 opens the circuit of the power magnet 318 and completes a circuit from ground through its outer back contact, left contact of spring 311, through the winding of sequence switch 310 to battery, driving the sequence switch into position 5.

In position 5 of sequence switch 310, a circuit closed from battery through the left-hand winding of relay 305, lower right contact of s iring 334t (5+6), lower left contact of said spring (5+5 to ground. Relay 305' operates and locks in the follou ing circuit, provided the first trunk in the group, upon the terminals of which the brushes 321, 322 and 323 are now standing, is busy: Battery, through the rigl'it-hand winding and inner front contact of relay 305 upper left contact of s ning 314; (5+7 upper right contact of said spring (5+10). brush 323 to the grounded test tcrmii'uil of the busy trunk. clay 305 at its outer front contact closes a circuit including the lower left contact of spring 312 for driving sequence switch 310 into position 6. Relay 305 remains energized in this position and completes a circuit through its outer front contact and the upper right contact of spring 312 (0) for the updrive power magnet 318, whereby the brush shaft 337 is driven upwardly to advance the brushes 32 322 and over the terminals of the groupto hunt for an idle trunk line. When the first idle trunk is reached, no ground potential being present upon the test terminal. the holding circuit of relay 305 is The loo

opened. This circuit, however, remain energized for an instant by means of a circnit from battery through the left-hand winding of said, relay, lower right contact of spring 334 (5+6), upper right contact of said spring (6), commutator E332, brush 329, lower right contact of spring 312 (6), outer front contact of relay to ground. When the brush 329 engages the next in, sulating segment of commutator 3212, relay 305 deenergized and the circuit of the magnet 318 is opened, causingthe brush shaft to cease its upward movement. Relay 305 at its outer back contact closes a circuit for driving the sequences switch 810 out of position 6 and into position 7.

1n position 7 of seqiiience switch 310, a circuit is closed from battery through the *ight-hand winding of relay 305, lower left contact of spring 309 (7), upper right contact of said spring (7 +16), lower contact of spring 316 (7+8), brush 322, trunk conductor 325, upper left contact of sequence switch spring 411 (17+15), lower right contact of said spring (1+8 to ground. Relay 305 becomes energized and closes a circuit through its outer front contact for driving sequence switch 310 out of position 7 into position 8. While sequence switch 310 is moving from position 7 to position 7%, relay 305 is held energized in a circuit from battery through the right-hand winding and inner front contact of said relay, upper left contact of spring 314 (5+7' lower left contact of said spring (6%+16%), to ground. When sequence switch reaches position 7%, the following circuit is closed for relay 305 in which said relay is mamtained energized after the sequence swltch has moved into position 8: from battery, through the right-hand winding and inner front contact of relay 305, lower right contact of spring 309 (T n-+8), upper right contact of sai d spring and thence to ground at sequence switch spring 4.11.

The trunk 324, 325 selectedv by the 1ncominn switch is held biiisy so as not to be selectaliile by other swilches by means of ground potential. placed on the test cou ductor 326. This potential is applied from ground through the lower left contact of spring 314 (G +16%), upper right con tact of said spring (5+16), test brush. 323 and thence to the multiple terminals of the test conductor 326 before all other switches.

The fundamental circuit for controlling the brush tripping movement of the final selector switch shown in Fig. 4 is now-completed and may be traced from battery through the winding of relay 400, lower leftcontact of spring 408 (1), lower contacts of spring 412 (15+6), conductor 324, brush 321, lower right contact of spring 315 (8), lower right contact of spring 306 (1+9), conductor 335, thence through the stepping relay 205 at the sender and returning as hereinbe'l'ore traced, over coi'idrmtor 336 to ground. at spring 307. Relay 400 and the stepping relay 205 operate in this circrut. Relay 400 closes a circuit from ground through its left front contact, lower right contact of spring 403 (1), windii' g of sequence switch magnet 410 tobattery, driving said sequence switch into position 2.

tion 2 of the sequence switch. establishes a circuit from battery through. the winding of the updrive power magnet 413, spring 406, closed in position 2, left front contact of relay 400 to ground. Magnet 413 causes the brush shaft 428 to be driven upwardly in the brush selecting 1n1ove1nent. Each time a brush tripping position is passed, a circuit is closed as follows for shunting the stepping relay 205 in the fundamental circuit: Battery, through the winding and right contact of relay 400, lower right contact of spring 408 (l+6),'lower right con tact of spring 412 (15+6), upper right contact of said spring (1 +2), comimitator 424, brush 422 to ground. At the end of the brush tripping movement, the fundamental circuit is opened at the sender and when thereafter the brush 422 moves on to an insulating segment of commutator 424, relay 400 deenergizes, opens the circuit of the magnet 413 and closes a circuit'through its left back contact and the upper right contact of spring 403 for driving sequence switch 410 out of position 2 and into position 3.

ln position 3 of the sequence switch 410, the fundamental circuit again closed and relay 400 attra its armal'inj'es and a ci cult is closed 0 er the lower ,it contact of spring 403 for dri'i 'iug sequence s-an'itci'i 410 into position 4. .ltehiy 400 remainim); energized in position 4 conuiletes the circuit hereinbefore traced including spring 406 for energizing the updrive power magnet 418. lVith the tripping magnet 414 energized in positions 3 quence switch in a circuit including spring 407, the subsequent upward movement of the brush shaft 428 in the group selecting operation trips the chosen set of brushes 416, 417 and 416, whereby the same are driven over the terminals the bank. For each group of the trunks traversed by the brushes, a circuit is completed as follows for shunting the stepping magnet 205: Battery, through the winding and right contact of relay 400, lower right contact of spring and 4 of the se fill Lil

lilo.

.iuagnet 413.

net 310 to battery. moves into position 10.

pleted in position of the sequence switch,

relay e00 operates and locks in the circuit above traced and completes a'circuit at its left frontcontact for driving sequence switch el-fl0outot position and into position 6. In this position a circuit is closed as previously traced tor the iupdrive power magnet all?) and the brush shaft 428 i-s-moved upwardly in the units selecting operation. During the units selecting movement ot' :the brush shaft, a circuit 313 .intermittently opened and closed as follows for shunting the stepping relay 205 in the fuiulainental circuit: Battery. through the winding and right contact of relay 100, lower rightcontact of spring 108, lower right contact of spring 6112, upper left contact, otsaid spring (5%+6), commutator 126, brush .4 23 to ground. Vhen the-brushes416, 117 and-418 are driven to the terminals of the calling subscribers line 130, the fundamental circult is mgened and immediately thereafter when brush Qii-engages an insulatingsegment of commutator 4126, relay 2ii00 deenergizes. and opens the circuit of the power 1 Relay 4100 also completes a circuit fordriving'the sequence-switch 410 out of position (land into position 15. At the time sequence switch 410 moved into'position 2, relay 401 was energized in a circuit-inclluling spring402 (2+18) and the grounded conductor 326.

Vi hen sequences switch 410 leaves position 8%, the circuit-hereinbeforetraced for relay 305 is opened, permitting this relay to become deenergized. Relay 305 completes a circuit from ground through its outer back contact, left contact of spring 311 (8), winding'of sequence-switch mag- Sequence switch 310 When the register sender 20-1 has coin-- plot-ed its function in controlling the selective movement of the switches, a ground mtential is applied to the com luctor 22? in the manner describedin the application by Allen, Serial No. 502, 17 1, filedSeptember 22, 1921. The application of :this ground results in the closure of .a circuit from battery through the right-hand windingof relay 208,1eft front contact of relay 207, brush 228 and thence to the conductor 297. Relay 208 operates an'dlocksin a circuit fflOlIl battery through resistances 200 and 210, left contact and left-hand winding of relay208'to ground. Relay 208 at its rightcontact. closes a circuit :tor relay 211. Relay 211 completes the conductors liSand 119 through to conductors 335 and-330, leading to the incoming switch and also app'lies aground potential to the terminal 220 and its multiples for rendering the trunk noneselectable. In addition, relay 211, closes a circuit from ground through its in inermostright contact, conductor 338, spring 308, upper rightcontact of sliiring 309 (7l16),lower left contact of said spring (EH-10), right-hand winding of relay 305 to battery. Relay 305 operates and closes a circuit from groundthrough its'outer front contact, lower left contact of spring 312 (10) winding of sequence switch magnet 310 to battery, drivingthe sequence switch out'of position .10a11d into position 15. Relay305remains energized .in the following circuit: Battery, through the right-hand winding and inner front contact of said relay, lower right contact of spring 309 (10 +16), upper right contact of said spring (7+16), and thence astraced to ground at the contact of relay 2 11. The switches remain in this condition until the toll operator has obtained connection with the called subscribers line and is ready to notify the calling subscriber that he may take up the conversation.

The toll operator by-means otthecalling end other talkingcord circuit 110 *proceeds to establish a connectio-nihrough plug 10 1 and jack 103 OV6I' l3l16 line 101, 102, which may lead through distant oflices,to the called subscribers line 100. Upon the insertion of plug 1041 in jack 1031a circuit is established from groundoverthe sleeves of jack 103andplug 104,1esistance 105, lamp 106 to battery. When the called subscriber answers, relay 109 :in theoperators cord circuit is placed in series with the called line and causes the supervisory lamp 100 to .be

shunted by the .fiow-of current through the resistances 107 and 105 to ground, as is obvious ifrom the disclosure. The operator noting that the called subscriber has answered proceeds to advise the calling sub scriberof this fact. She thereupon seizes the plug 116 of the holding cord 115 and withdraws itfromthej-ack 1,17 and then in sorts the plug 112, of the talking cord cir-- cuit 110 i11-the jack 117, thus muting the called=a11dcalling subscribers telephon ica l ly.

Instantly, that the holding cord 11 is removed, the circuit for relay 20Tris opened. illelay 207,;011 deenergizing, completes a circuit from battery through the winding of relay212, 'lett c-ontactot relay 211, inner right contact of relay 207, make-beforebreak contact at the outer right-hand armature of relay 212, conductor 229, "terminal.

ground.

' the winding of saidrclay, left contact of relay 211, inner rightcontact oligrclay 207f to ground at the outermost right contact of relay Relay 212 at its middle contact closes a circuit for relay- Relay 21-1 complets a circuit from ground. through the constantly rotating interru1'iter 215, inner contact oil. relay 21 1, Winding of stepping magnet 213-toi battery. Each time the interrupter 2l5 -closes, the stepping magnet 213 is energized and upon the release there offadvances the brushes 216, 217 and 218 forward one step. The speedof the interrujiater 215 is so taken that some desired interval is required forthe switch 2 to take a number of steps necessary for the brush 218 to make engagement with the terminal I i o 219. Obviously-this interval maybe adjustedto any desired value and is so cal culated as to allow the operatlor'ample time ii shemakes' to change hercord circuits. the change regularly within the time allowed her for that'purpose, theinser'tion of plug 7 112 in the jack 117 result-sin the closure of: a newcircuit for relay 7, traceable from .batterythrough the winding ofrelay 113,-

conductor 120,

thence over the sleeve through the winding of relay 207 to ground. Relay 207, upon reenergizing, opens the c1rcuit of relay 212, which in turn,-o-p ens the circuit of relay 214, thereby severing ,tlieinterrupting circuit of stepping magnet 213. 'lhe stepping magnet 213 is now energizedin a self-interrupting circuit i i-om battery through its winding and-contact brush'217 and its connected terminals to ground at the outer contact of relay 214. lhestepping magnet interrupts its own circuit and ad vances 'the circuit oii--the time measure switch until they have reached their; next normalposition, at which time, brush 217 rests on the disconnected terminal 241-, open-' ingtheinterrupting circuit oi -the mam 'llhe toll operator nowproce'eds to apply ringing 01111781111110 the calling subscribefsline 4.30 Irv operating her ringingkey 121. The operation of this key completes a oncuit from the ringing source'122, lower contact of key 121, ring of plug 112, ring of jack 117, conductor 110, middleright con tact 0:1- relay 2-1-1, conductor 336,'upper and lower right-contacts of spring 307- (10{-16),* V

circuit 01 relay 21ft andv relay 21 1, as above lo werleft-hand Windingof repeating coil 339,

winding of relay 802, condenser 340, upper left-hand winding of coil 389, upper right and lower left contacts of spring ,306

'(-1.0+16),conductor 335, outermost right a-ieiitact o1 Malay 211,conductor 11 8, tip'ofjack 117, tip oi?- plug 112, upper contact of key 121 to ground. Relay 302 respondsto the alternating current from the source122 and closes a circuitfor relay 304:. Relay 304: completes a-circuit for applying ringing current from the source 341-1, over the calling subscribefls 11116 loop 430, returning to ground at the upper front contact of relay 1-; lVhen the calling subscriber takesthe receiver oil the switchhook, having been in structed previously to replacethe receiver during the time n which the connection is being obtained, and when relay 30a isdeenergized on the release of the ringingkey 121, a circuit is closedfrom battery through the winding of relay 303, lower right-hand winding of coil 339, lower back contact of relay 30a, thence over the subscribersline and returningto ground through the upper right-hand winding of repeating coil 339. Relay 303 closes acircuit for the operation of relay 301 and relay 301 opens the circuit which has existed, including the retardation coil 300 and the right-hand windings of the repeating coil 108 in the operators cord toll operator for some reason or other neglects to change the cord circuits within the predetermined interval of time. In this event, the timemeasure switch 2410 has sur'l'r cient time to advance the hrush 218 into engagement with contact 219, prior to the -reenergizati01rof relay 207 and the consequent deenergization of relay 212. Hence, a circuit is closed from ground, through the brush 218, terminal 210, innermost contact of relay 212,resistanc'e 209 to battery. 'lihis direct circuit to ground shunts the holding circuit previously traced through. the loith'and winding of relay 208, whereby this relay releases its zll'lilillltll'QS. Relay 208 opens the circuit otrelay 211,111'11611-lll-l lllll, re

switch .magneteiO to battery Sequence switch 310 moves outottposition 15, over position 16 and into PpositionlS.

lVhen relay 212 "deenergizes it epens the described, opens the interrupting circuit oi the stepping magnet'213. The brush 218 now standing .on the. terminal 219, while hrush 21? has one position :to advance. in order tov reach normal.

Hence, the inter mination of lamps 111 and 106.

(iii

causes the brush shatt to he closed from battery through "the winding o't sequence switch magnet 310, righthand contact'of spring 311 '(3-l-18) ,segment 333, brush227, to ground. Sequenceswiteh 310 moves into position land the circuit of power magnet 820 is opened.

hen sequence switch 310 leaves position 10,, it opens at the upper right contact of spring 31 1, the circuit of relay 401. Belay =l0'1. becomes deenergized andcloses a circuit from ground through its contact, upper left contact of spring 403 ('15), winding of sequence switch magnet 110 to battery. Se-

qluince switch 410 is moved from position 15 into position 18, where a circuit is closed from battery through the winding of down drive power n'iagnet 41 5, spring 105 (18), to ground. lVhen the brush shaft 4:28 re-ache s normal'position a-circuit is closed including springs-0 1 (18) and the'segment 1-27 for driving sequenceswitchllO out of position 18 and into position 1.

The time measure switch 2t0-is common to all trunks such trunk 1.18, 119, and is associable with. any one by the energization of the individual relay 212. It the switch is in use and moving from'one normal position to another at the time the relay 207, individual to a second trunk, is deenergized, the circuit for the corresponding relay 212 cannot be energized until the brush 210 has reached its next normal position terminal for the reason. that all intern'iediate terlninals are disconnected-as shown. This ar- 'rangement avoids the simultaneous association of the commonswitch 'witlra plurality of trunks while the switch 18 in operation interval. the release of the connection following the tcrmiiuition of conversation takes place in the mannersimilar to that already explained. When the calling and called subscribers replace "their receivers on the switchhoolzs, the supervisory relay 111 in the operators cord. circuit is energized while the supervisory relay 109 is deenergizcd, causing respectively, the illu- The operator, noting these lamps, removes the plugs i: and 112 01 her cord circuit from the jacks 1103 and 117. The deenergizatiou of relay 207, following the removal. of the cord circuit from the trunk 118, 119 initiates in the manner explained, the movement o 't the switch 240, which at the end of an interval, causes the release of the incoming and final switches.

lVha-t is claimed is:

1. l'n ateleplmne system, selective switches, a plurality of trunks each leading to certain of said. switches, means for establishing a connection to any of said .trunks,means for operating the selective switches toextend such trunk, a time measuring device common to said trunks, means responsive to the disestablishment of said connection for operating said device, and means operated by said device after-a deliaiite interval tor releasing the selective switches.

2. In a telephone systenn'selective switches, a plurality ot trunks each leading to certain of said switches, means for establishing a connection to one of said trunks, means for operating the selective switches to extend said trunk, a time measuring device common to :all trunks and associable with any one thereof, means responsive to the disestablishment of said connection forstartingthe time measuring device in operation and for associating "the same with said trunk, and means operated by said device atter a definite interval tor releasing the selective switches.

33. In a telephone system, selective switches, a plurality oi? trunks each leading to certain ott'said switchesymeans toresta-blishing a n'lfil'lllttl connection to one of said trunlrs, means tor operating the selective switches to extend said trunk, '21 time measuring device common to said trunks. means responsive to the disestahlishment ot' the ananual connection from saidtrunk for operating said device, and means operated by said device alter a definite interval for releasing the selective switches.

1. In a telephone system, selective switches. a plurality of trunks each leading to certain of said switches, means forestablishing a. connection to one of said trunks, means for operating: the selective switches to extend said trunk, a self-operated time nmasurhug; device common to said trunks, means responsive to the disestahlisluneut oi? said coimection for opt-mating said device, and means operated by said device after a definite interval for releasing the selective switches.

5. In a telephone system, selective switches, a plurality of trunks each leading to certain of saidswitches, meansforestablislr ing a connection to one of said trunks, means for operating the selective switches to extend said trunk a time measuring switch common to said trunks, means rc sponsive to the disestablishment of said connectzonfor operatmgsaid switch in a steplay-step manner, and means operated by said switch attcr it has moved through a certain distance for releasing said selective switches.

(i. In a telephone system, an opera-tons position, selective switches, a plurality of trunks each leading from the operators position to certain of said switches, means at the operatofis position for establishing a connection with one of said trunks, means for operating the selective switches to extend said trunk, atime measuring device common to all. trunks, means effective when the connection with said trunk is disestablished at- .the o )erators )osition for eratin said device, and means operated by said device I after a definite interval for releasing the selective switches.

7. In a telephone system, selective switches, a plurality of trunks each leading to certain of said switches, means for establishing a connection to one of said trunks, means for operating the selective switches to extend.- said trunk, a time measuring device common to said trunks, means responsive to the disestablishment of said connection for operating said device, means operated by said device after a definite interval for releasing the selective sw1tches, andmeans for rendering sa1d device ineffective to release the selective switches if said connection is reestablished beforesaidinterval expires.

8. Ina telephone system, selective switches, a plurality of trunks each leading Y. to certain of said switches, means for estabv hshzng a connectlon to one of said trunks,

means for operating" the selective switches to extend said trunk, a time measuring device common to all of said trunks and associable with any one thereof, means responsive to the disestablishment of said connection for starting the device in operation and for associating the same with said trunk, means opcrated by said device after a definite interval for releasing the selective switches, and means for rendering said device inefifective to release the selective switches it said connection is reestablished before said interval expires.

rendering said timelineasuring switch inetlishingr a connection to one of 'tlcctive to release the selective switches it said connection is reestablshed belorea deii 'nite number of steps have been taken.

10.111" a telephone system, an operators position, selective switches, a plurality of trunks each leading from the operators position to certain of said switches, a cord circuit at the operators position for establishinga connection with one of said trunks, 'meansl or operating the selective switches to extend. said trunk, a time measuring device common to all trunks, meanseil'ective when said. cord circuit is disconnected from said trunk for operating the time measuring device, and means operated by said device after a definite interval for releasing the selective switches. I

11. In a telephone system, an operators position, selective switches, a plurality of trunks each leading from the operators position to certain of said switches, a plurality of cord circuits at the operators position each serving to establish a connection with one of said trunks, means for operating the selective switches to extend said runlrs, a time measuring device common to all trunks, means effective when the operator disconnects a cord circuit from a trunk for operatingsaid device, means operated by said device alter a definite interval for releasing the selective switches, and means for rendering said device ineffective to release the selective switches if the operator reestablishes the connection to said trunk with one of the cord circuits before said interval expires.

12. In a telephone system, selective switches, a plurality of trunks each leading to certain of said switches, means for establishing a connection to one of saidtrunlrs,

means for operating the selective switches to.

extend said trunk, a time measuring device having a plurality of normal positionsand common to all. of said trunks, means responsive to the disestablislnnent of said connection for starting said device from one of its normal positions, and means operated by said device alter a definite interval for releasing the selective switches.

.13. In a telephone system, selective switches, a plurality of trunks each leading to certain of said switches, means for estabsaid trunks, means tor operating; the selective switches lo exteml said trunk, a time measuring device having a plurality of normal positions and arranged in common to all of said trunks, means responsive to the disestablishment of said connection for initiating the operation of said device from one of its normal positions,'means operated by said device after a definite interval for releasing the selective switches, and means for rendering said device ineifectilve to release the selective switches it said connectionv is reestablished bet'ore said interval expires.

14. In a telephone system, selective switches, a plurality of trunks each leading to certain of said switches, means for establishing a connection to one of said trunks, means for operating the selective switches to extend said trunk, a time measuring device common to all of said trunks and associable with any one thereof, said device hav-- ing a plurality of normal positions, means responsive to the disestablishment of said connection for associating said device with said trunk and for starting the same in operation from one of its normal positions, means operated by said device after a definite interval for releasing the selective trunks, means for operating the selective switches to extend such trunk, means for holding the selective switches in their operated condition, a time measuring device common to said trunks, and means operated by said device for controlling said holding means to cause the release of said switches.

16. In a telephone system, an operators position, selective switches, a plurality of trunks each leading from the operators position to certain of said switches, a plurality of cord circuits at the operators position for connection with any one of said trunks, means for operating the selective switches to extend such trunk, holding means dependent on the connection of one of said cords with said trunlc for holding the selective switches, a time measuring device responsive to the disconnection of a cord from said trunk and arranged to measure an interval sufiicient for the operator to disconnect one cord from and connect another one to said trunk, and means operated by said device at the end of such interval for controlling said holding means to release the selective switches.

17. In a telephone system, selective switches, a plurality of trunks each leading to certain of said switches, means for establishing a connection to any one of said trunks, means for operating the selective switches to extend such trunk, and means common to said trunks for holding the selective switches associated with any one o't said trunks for a predetern'lincd interval (it time following disconnection therefrom.

18. In a telephone system wherein operators cord circuits are used for extending connections, selective switches, a plurality of trunks each leading to certain of said switches, means including said cord circuits for establishing a connection to any one of said trunks, means for operating the selective switches to extend such trunk, and means common to said trunks for holding the selective switches associated with such trunk while the operator is changing from one cord to another.

19. I11 a telephone system, selective switches, a plurality of trunks each leading to certain of said switches, means for establishing a connection with any one of said trunks, means for operating the selective switches to extend such trunk, a time measuring device associable with any one of said trunks, means effective on the disestablishment of said connection for operating the said device, and means controlled by said device for holding the selective switches during such disestablishment.

20. In a telephone system, an operators position, selective switches, a plurality of trunks each leading from the operators position to certain of said switches, means controlled by the operator for operating and holding the selective switches to extend one of said trunks, a timing device associable with any one of said trunks, and means operated by said device for releasing the selective switches after a definite interval following the release of such trunk.

21. In a telephone system, an operators position, selective switches, a plurality of trunks each leading from the operators position to certain of said switches, means controlled by the operator for operating and holding the selective switches, a time measuring device common to all. but associable during its operation with one only of said trunks, and means controlled by said device for holding the selective switches upon the disestablishment of the connection.

In witness whereof, I hereunto subscribe my name this 20th day of September A. D.

FREDERICK J. SOUDDER. 

